This invention relates to devices for measuring air flow through duct systems and, more particularly, to a device for measuring the total static pressure of a duct system in order to measure the total volume of air flowing from the duct system for a particular type of environment conditioning plant.
A structure built for human occupation, such as a building, or a recreational vehicle is often provided with an environment conditioning system for heating and/or cooling the structure. A conventional environment conditioning system includes an environment conditioning plant, such as an air conditioner or a heat pump, and a duct system for delivering conditioned air from the plant to different areas or rooms within the structure.
When providing an environment conditioning system for a structure it is important to provide a desired flow of conditioned air into each of the various rooms or areas within the structure. Therefore, it is important to be able to measure the total volume of air flowing from the duct system for a particular type of plant. Often, the total volumetric air flow must be measured several times for different plants to ensure that an adequately-sized plant is provided.
Conventionally, the total volume of air flowing from a duct system is obtained by measuring the individual volumetric air flows from the various outlet vents of the duct system and then adding them together. Typically, the individual volumetric air flows are measured using a rotary vane anemometer, a hot wire-type anemometer, or a pitot tube anemometer. At each outlet vent, the velocity (in feet per minute) of the air is measured using the anemometer. The velocity is then multiplied by the cross-sectional area of the outlet vent to obtain the volumetric air flow from the outlet vent.
As can be appreciated from the foregoing, measuring the total volumetric air flow from a duct system for several different plants is a time consuming endeavor. The plants must installed and un-installed and a multitude of air flow measurements must be taken. Accordingly, there is a need in the art for a simpler apparatus and method for measuring the total volume of air flowing from a duct system for a particular type of plant. The present invention is directed to such an apparatus and method.